Power one-way drive engaging wrench



June 4, 1968 J. w. BLOOM I 3,386,319

7 POWER ONE-WAY DRIVE ENGAGING WRENCH Filed Aug. 29, 1966 fi INVEJV'TUR.James d l 6/00/22 ATTQ NE United States Patent 3 386 319 rowna ONE-WAYnnrvn ENGAGING WRENCH James W. Bloom, Montvale, NJ., assignor to GeneralMotors Corporation, Detroit, Micln, a corporation of Delaware Filed Aug.29, 1966, Ser. No. 575,630 2 Claims. (Cl. 81-54) ABSTRACT OF THEDESCLOSURE This invention relates to a power wrench and moreparticularly to a power one-way drive engaging wrench of the open endtype employing an oscillator drive for oscillating the Wrench head andpositioning the head in an open position for wrench removal.

In prior power wrenches, the wrench head is generally continuouslyrotated in one direction or the other to turn an object, such as a nut,to effect loosening or tightening of a threaded fitting. While wrenchesof this type have proven generally satisfactory with closed end heads,these wrenches present problems in applications, such as tube fittings,where an open end head is required. Because of the rotary head motion,the open side of the head may stop in a closed or obstructed positionupon tightening the fitting thereby requiring operator time to index thehead to the open position to enable wrench removal from the tubing.

The power wrench of the present invention employs an oscillatory headproviding one-way drive operation for engaging and turning an object tobe turned and an oscillator drive operable with both a unidirectionaland a bidirectional power input to oscillate the wrench head. The powerwrench is illustrated as comprising an open end one-way drive engaginghead having guided, spring biased engaging rollers for engaging theobject to be turned, which may be a nut and an open end which isunobstructed in an open position. The head is operable when oscillatedto have the rollers drivingly engage and rotate the nut in one directionwhen the head is swung in the one direction and release the nut when thehead is swung in the opposite direction. The oscillator drive foroscillating the head includes a rotary input member powered by a powerunit and having a cam. Reciprocating linkage is connected at one end tothe head and has a cam follower at the other end biased by a springagainst the cam. The spring biased cam follower cooperates with the camto position and hold the input member in a normal position when there isno power input so that the linkage positions the head in its openposition for insertion over a tube to enable engagement with the tubesnut fitting. When the input member receives power input, the camoperates on the linkage to oscillate the head and 3,336,319 PatentedJune 4, 1968 ice turn the nut. Upon interruption of power input, thespring biased cam follower cooperates with the cam to rotate the inputmember to position the head in its unobstructed open position. Since thehead operates in only a relatively small are as compared with a 360rotating pattern, there is considerably less possibility for the openend head to stop tightening in a closed or obstructed position. If thehead does stop in a closed or obstructed position, it is returnedautomatically to its normal open position when the power input isdiscontinued. Thus, operator time is saved because of the considerableless possibility of the open end wrench stopping in a closed orobstructed position, and in the event that it does stop in an obstructedposition, the self-indexing feature will return the head to its openposition. Another feature of the present invention is that theratcheting action occurs in the head and not in the oscillator drive sothat the object being turned is part of the wear surface whereby theoscillator drive maintenance requirements are reduced.

An object of this invention is to provide a power wrench having a headoperable when oscillated to drivingly engage and rotate a member in onlyone direction and an oscillator drive operable with both aunidirectional and a bidirectional input to oscillate the head.

Another object of this invention is to provide a power open end wrenchhaving a head whose open end is unobstructed in an open position and anoscillator drive for driving the head and for biasing the head to theopen position when power input is discontinued.

Another object of this invention is to provide an oscillatory open endhead having a one-way engaging drive operable to drivingly engage anobject when the head is swung in one direction and release the objectwhen swung in the opposite direction and also having an open end whichis unobstructed in an open position and an oscillatory drive having arotary input and a spring biased cam drive for connecting the rotaryinput to the head and maintaining the head in the open position whenthere is no power input and converting rotary input movement intooscillatory movement of the head upon power input and biasing the headto the open position when power input is discontinued.

These and other objects of the invention will be more apparent from thefollowing description and drawing in which:

FiGURE l is a longitudinal view with parts in section of the powerwrench of the present invention.

FIGURE 2 is a view taken on the line 2-2 in FIG- URE 1.

FIGURE 3 is a view taken on the line 33 in FIG- URE 1.

FIGURE 4 is an enlarged view of the wrench head shown in FIGURE 1 withadditional parts being shown in section.

FIGURE 5 is a partial perspective view of the wrench head showing atypical application of the tool.

In the illustrated embodiment of the present invention and referring toFiGURE l, the power wrench generally comprises a power unit 19 driveconnected by an oscillator drive assembly 12 to a head assembly 14. Thecomplete wrench assembly which is compactly arranged about a commoncentral longitudinal axis, is of the open end type.

The power unit includes a casing 16 housing suit able power means suchas a hydraulic, electric or pneumatic motor which is operable by amanual control 17 to selectively rotate a wrench input member or spindle18 and also permits the spindle to be rotated by the oscillator drivewhen the power is turned off as described in detail later. The spindleis rotatably mounted in the casing on a sleeve bearing 1? and a thrustball bearing 20 and is provided at its outer end with a barrrel cam 22having a single lobe 24.

The oscillatory drive assembly 12 and head assembly 14 are detachab lysecured to the power unit by having their common frame 26 internallythreaded and screwed upon a threaded flange integral with the power unitcasing 16. The frame 26 has a circular chamber 28 adjacent the powerunit accommodating the cam 22 and also has an elongated, fiat portion orarm 31 for supporting the head assembly 14 and also the reciprocatinglinkage drive connecting the cam to the head. The linkage, as best shownin FIGURES l, 2 and 3, comprises a rod 32 and a rod 34 which arereceived and guided by channels provided by the opposite edges of arm31B and a pair of side plates 36 and 38 which are secured to theopposite sides of arm 30 by a pair of bolts 40 and 42. A pair ofcantilevered spring members 44 and 46 are secured at their bases to theframe 26 by pairs of screws -48 and 50, respectively, and have theirrespective finger tips 52 and 54 slidably engaged by the rods 32 and 34.

One end of rod 34 is provided with a yoke 56 which is received andguided in an elongated slot 58 provided in frame 26. Coaxial aperturesin the yoke arms receive a pin 60 which rotatably supports a camfollower or roller 62 mounted between the yoke arms and having a rollingsurface e-ngageable with the cam surface of cam 22. One end of pin 60extends past the outer side of the inner yoke arm, and a coil spring 64,which is received in a blind bore 66 at the center of the frame, actsthrough a plunger 68 which bears against the pin 69 so that the roller62 is maintained in contact with cam 22. An elongated slot 69 in theframe receives the pin extension upon sufiicient leftward pin movement.

The rods 32 and 34 are linked by a pivotal lever 70 which is received ina side recess 71 in arm 31 and contrally pivoted on the shank of bolt42. Lever 70 has one rounded end 72 received in a side recess '74 in rod34 and the other rounded end 76 received in a side recess 78 in the rod32 as shown in FIGURES 1, 2 and 3.

Upon rotation of the spindle 18, the roller 62 is caused to follow thecontour of cam 22 thereby causing reciprocal movement of both rod 32 androd 34. The reciprocal motion of the rods is 180 out-ofphase with rod34- being pushed to the left and the swinging link 73 pulling rod 32 tothe right as roller 62 rides up the cam surface towards the apex of lobe24 whereafter the spring 64 maintains contact of the roller 62 with thecam surface so that it rides down the other side of the lobe under thebiasing action of the spring to pull rod 34 to the right and push rod 32to the left. Thus, the rotary input has thus far been converted by theoscillator drive into reciprocating movement of the rods 32 and 34 whichmovement will occur regardless of the power input drive direction ofpower unit 10.

The head assembly 14, as best shown in FIGURES 1, 2, 4 and 5, comprisesa cylindrical head plate 80 provided with a circular aperture 82 havingan arcuate opening 84 at the forward portion of the head plate. A seriesof contiguous and intersecting grooves 86 and 88 of equal diameter buthaving offset and parallel axes are equally spaced about the innerperipheral surface of head plate 80. The grooves 86 and the deeper andintersecting grooves 88 provide a series of cam surfaces for receivingpawls provided by rollers 90. Rollers 90 have a diameter equal to thatof the grooves 86 and 88 so that the roller surfaces are capable of fullgroove contact with the groove surface of either the grooves 86 or 88.The grooves 86 and 88 are arranged so that when the rollers are disposedin the deep grooves 88 they do not protrude substantially into theaperture 32 enabling the head to turn freely about objects such as a hexnut tube fitting 91. When the rollers are disposed in the shall-owgrooves 86, a substantial portion of each roller extends into theaperture to provide a gripping action to turn the nut.

The rollers are supported by arcuate side plates 92 and 94 which do notobstruct the head plate openings 82 and 84 and are secured to theopposite sides of the head plate by rivets 95. Each side plate has aseries of apertures 96 receiving pins 98 extending from the oppositeends of the rollers. Each roller 91) is normally urged to a maximumextended position by an elongated coil spring 102 disposed radiallyoutward of each roller in a slot 104 in head plate 80, the springs hookends being connected by pins 106 to the head plate at opposite sides ofhead opening 84.

The apertures 96 in the side plates are larger in diameter than theroller pins 93 and overlie the intersections of the grooves 36 and 88 sothat swinging movement of the rollers occurs with the rollers rollingover the intersection of the adjacent groove walls. The rollers arethereby always in contact with a wall of one or the other of thegrooves, the engagement of the roller pins 98 with the side walls of theapertures 96 merely serving to guide the rollers in their swingingmovements, to limit their radially inward displacement by the spring 102and to keep the rollers always in contact with the side walls of one ofthe grooves 86 or 88. The pins 98 do not bear the work loads of therollers, the work load being directly transmitted to the walls of thegrooves 86.

The side plates 92 and 94 have a reduced diameter at their outer sidesas best shown in FIGURE 5 to provide collars or shoulders which arereceived in coaxial aper tures 108 and 1111 provided in the frame sideplates 36 and 38 respectively whereby the head assembly is capable ofoscillatory movement about its axis 111. Apertures 108 and 110 arecontiguous with arcuate openings 112 and 114, respectively, through theforward ends of the frame side plates 36 and 38, respectively, whichopenings permit entry to the head opening 84.

Lugs 116 and 118 provided on the arcuate ends of rods 32 and 34,respectively, are respectively received in accommodating recesses 120and 122 provided in the head plate '80, the recesses and thus the luglocations being diametrically opposed, i.e., apart. The spring members44 and 46 respectively hold the lugs 116 and 118 continuously engagedwith the head. Thus, reciprocating movement of the rods 32 and 34 iseffective to oscillate the head assembly. During oscillating headmovement, the rods 32 and 34 swing through a small are because of theirlug connection with the head which swinging movement is permitted by theflexible spring members 44 and 46 respectively.

The spring force of spring 64 and the slope of the cam surface of cam 22is determined so that when there is no power input from power unit 10,the spring biased cam follower cooperates with the cam to normally holdthe cam in the zero cam lift position shown in FIGURE 1 so that the rods32 and 34 assume the full line positions shown in FIGURES 1 and 4. Inthe full line position, the head assembly is positioned in What ishereinafter described as the normal open position with the head opening84 aligned with the frame side plate openings 112 and 114 to permitentry to and exit from the head aperture 82.

As illustrated in FIGURE 5, the open end of the power wrench permits thewrench to be slipped over a tube 124 whereafter the wrench is movedaxially along the tube to position the head assembly on the hex nut tubefitting 91 which is desired to be threaded into the fitting 126. Theoperator then operates the power unit 10 by the control 17 to rotate thespindle 18, which rotational direction may be in either direction. Thereciprocating rods and cam drive convert the rotary input of the powerunit into oscillating movement of the head assembly.

Upon clockwise swinging movement of the head assembly as viewed inFIGURE 4, the nut engages the adjacent extending rollers 90 to initiallydisplace the contacted rollers to their seated position in the shallowgrooves 86. Further roller displacement is thereafter prevented so thatthe continuing clockwise swinging movement of the head assembly causesthe immovable rollers to drivingly engage and effect rotational movementof the nut in the same direction. The head assemblys clockwise movementterminates at the dash line position shown in FIGURE 4 which occurs whenthe cam apex contacts the follower whereafter the head assembly is swungin the opposite or counterclockwise direction by the spring action.Swinging movement of the head assembly in the counterclockwise directionon the remaining half of the cycle initially causes the rollers, whencontacted by the nut edges, to be displaced in the direction towards thedeep grooves 88 so that the rollers are sufliciently withdrawn from thehead aperture to enable the nut to remain stationary within the headaperture while the head assembly continues to swing counterclockwise.

Thus, the complete cycle is composed of an unyielding force transmittingdrive to the head assembly in one direction for turning the nut and abiasing force to turn the head assembly in the opposite direction whilethe nut remains stationary, the head assembly cycling until the nut istightened. The power unit is preferably of the type which stalls afterthe threaded element has been set with a predetermined torque.

Since the head operates in a relatively small are dependent on the pawlspacing which increases with Increasing nut head size and may be in the30 to 60: range, for example, as compare with a full 360 rotatingpattern, there is a considerably greater chance that the head opening 84will stop in an unobstructed or the norm l open position when the nuthas been tightened to permit wrench removal from the tubing. If the headdoes stop tightening in a closed or obstructed position, it is returnedautomatically to its normally open position by the return actionprovided by the predetermined spring biased cooperation of the camfollower and cam, i.e., the spring 64 biasing the roller 62 against thecam 22 urges the spindle 18 to rotate and seek the zero cam liftposition shown in FIGURE 1. Thus, the wrench has a much reducedpossibility of completing the tightening cycle In a closed positionbecause of both of the aforementioned factors and does not require anoperator indexing operation to enable removal of the wrench from thetubing. Furthermore, the oscillator drive is a simple constructionhaving low maintenance requirements since the ratcheting action occursin the head assembly. 7

Similar wrench operation to loosen the nut is provided by turning thewrench 180 in either direction about its longitudinal axis. The deepgrooves 88 are then disposed counterclockwise of their adjacent shallowgrooves 36 so that the nut is turned in the counterclockwise directionin response to oscillating head movement.

The above described preferred embodiment is illustrative of theinvention which may be modified within the scope of the appended claims.

I claim:

*1. In a wrench assembly the combination of support means having a sideopening only substantially as wide as an object to be turned and rotarybearing means only interrupted by said side opening; an opened endwrench head mounted in said bearing means on said support means foroscillatory movement; said wrench head having a side opening onlysubstantially as wide as the object to be turned to receive the object,a bearing surface .only interrupted by said side opening in said wrenchhead and one-way engaging means for engaging the object to be turnedwhen said wrench head is turned in one direction and releasing theobject when said Wrench head is turned in the opposite direction; saidside opening of said wrench head being substantially aligned with saidside opening of said support means for unobstructed reception of theobject to be turned into the side opening of said wrench head when saidwrench head is in an open position at one end of said oscillatorymovement and being aligned with said side opening of said support meanswhen said wrench head is in a relatively large range of obstructedpositions and a final obstructed position at the other end of saidoscillatory movement; and drive means including a rod mounted on saidsupport means for reciprocal movement, pivot means connecting .one endportion of said rod to a substantially fixed point on said wrench headfor providing a drive connection to oscillate said wrench head betweensaid open and final obstructed position when said rod is reciprocated, arotary input having cam means, said rod having a cam follower engagingsaid cam means, spring means operatively biased between said supportmeans and said cam follower for holding said cam follower in engagementwith said cam means, said cam means reciprocating said rod to oscillatesaid wrench head between the open and final obstructed position whensaid input member is rotating in response to a rotary input, said springmeans providing .a spring force and said cam means having -a profilecooperatively providing for rotating said input member to operate saidrod to turn said wrench head with sufiicient force to disengage saidone-way engaging means and to move said wrench head from any of saidobstructed positions to said open position upon freeing said inputmember on discontinuance of rotary input to said input member.

2. In a wrench assembly the combination of support means having a sideopening substantially as wide as an object to be turned and rotarybearing means only interrupted by said side opening; an open end wrenchhead mounted in said bearing means on said support means for oscillatorymovement; said wrench head having a side opening only substantially aswide as the object to be turned to receive the object, a bearing surfaceonly interrupted by said side opening in said wrench head and onewayengaging means for engaging the object to be turned when said wrenchhead is turned in one direction and releasing the object when saidwrench head is turned in the .opposite direction; said side opening ofsaid wrench head being substantially aligned with said side opening ofsaid support means for unobstructed reception of the object to be turnedinto the side opening of said wrench head when said wrench head is in anopen position at one end of said oscillatory movement and beingunaligned with said side opening of said support means when said wrenchhead is in a range of obstructed positions and a final obstnuctedposition at the other end of said oscillatory movement; and drive meansincluding a pair of rods mounted on said support means for reciprocalmovement, recesses .on opposite sides of said wrench head, one end ofeach said rod having a lug pivotally received in a recess in said wrenchhead for providing a drive connection, springs for holding said rods toposition said logs in said recesses during rod reciprocation tooscillate said wrench head, a lever mounted .on said support means forpivotal movement and engaging said rods on opposite sides of said leversfulcrum whereby both said rods are reciprocated in opposite phaserelation and oscillate said wrench head between said open and finalobstructed position when one of said rods is reciprocated, a rotaryinput member having cam means, said one rod having a cam followerengaging said cam means, spring means operatively biased between saidsupport means and said cam follower for holding said cam follower inengagement with said cam means, said cam means reciprocating said onerod to oscillate said wrench head between the open and final obstructedposition when said input member is rotating in response to a rotaryinput, said spring means providing a force and said cam means having aprofile cooperatively providing for rotating said input member tooperate said one rod to turn said Wrench head with sufficient force todisengage said one-Way engaging means and to move said wrench head fromany of said obstructed positions to said open position upon freeing saidinput member on discontinuance of rotary input to said input member.

References Cited UNITED STATES PATENTS JAMES L. JONES, JR., PrimaryExaminer.

